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extern crate futures;
extern crate hyper;
extern crate rand;
extern crate tokio_core;
extern crate trust_dns;
use trust_dns::client::ClientHandle;
use rand::Rng;
use hyper::net::{NetworkConnector, NetworkStream};
#[derive(Debug, Clone)]
pub struct DnsConnector<C: NetworkConnector> {
connector: C,
dns_addr: std::net::SocketAddr,
}
impl<C: NetworkConnector> DnsConnector<C> {
pub fn new(dns_addr: std::net::SocketAddr, connector: C) -> DnsConnector<C> {
DnsConnector {
connector: connector,
dns_addr: dns_addr,
}
}
}
impl<C: NetworkConnector<Stream = S>, S: NetworkStream + Send> NetworkConnector
for DnsConnector<C> {
type Stream = S;
fn connect(&self, host: &str, port: u16, scheme: &str) -> hyper::Result<S> {
let mut io =
tokio_core::reactor::Core::new().expect("Failed to create event loop for DNS query");
let (stream, sender) = trust_dns::udp::UdpClientStream::new(self.dns_addr, io.handle());
let mut dns_client =
trust_dns::client::ClientFuture::new(stream, sender, io.handle(), None);
let (host, port) = match host.parse() {
Err(_) => {
let name = trust_dns::rr::Name::parse(&format!("{}.", host), None).unwrap();
match io.run(dns_client.query(name,
trust_dns::rr::DNSClass::IN,
trust_dns::rr::RecordType::SRV)) {
Ok(res) => {
let answers = res.get_answers();
if answers.is_empty() {
return Err(std::io::Error::new(std::io::ErrorKind::Other,
"No valid DNS answers")
.into());
}
let mut rng = rand::thread_rng();
let answer = rng.choose(answers)
.expect("Sort out what to return here");
let srv = match *answer.get_rdata() {
trust_dns::rr::RData::SRV(ref srv) => srv,
_ => {
return Err(std::io::Error::new(std::io::ErrorKind::Other,
"Unexpected DNS response")
.into())
}
};
let target = srv.get_target();
let additionals = res.get_additionals();
let entry = additionals
.iter()
.find(|additional| additional.get_name() == target);
if let Some(entry) = entry {
let addr = match *entry.get_rdata() {
trust_dns::rr::RData::A(ref addr) => addr,
_ => {
return Err(std::io::Error::new(std::io::ErrorKind::Other,
"Did not receive a valid record")
.into())
}
};
(addr.to_string(), srv.get_port())
} else {
return Err(std::io::Error::new(std::io::ErrorKind::Other,
"Did not receive a valid record")
.into())
}
}
_ => {
return Err(std::io::Error::new(std::io::ErrorKind::Other, "Failed to query DNS server")
.into())
}
}
}
Ok(std::net::Ipv4Addr { .. }) => (host.to_string(), port),
};
self.connector.connect(&host, port, scheme)
}
}
#[cfg(test)]
mod tests {
#[test]
fn it_works() {}
}